General Overview of Types of Pumps on Ship
A ship consists of various types of fluids moving inside
different machinery and systems for the purpose of cooling, heating,
lubrication, and as fuels. These liquids are circulated by different types of
pumps, which can be independently driven by ship power supply or attached to
the machinery itself. All the systems on board ship require proper operational
and compatible pump and pumping system so that ship can run on its voyage
smoothly.he
selection of a type of pump for a system depends on the characteristics of the
fluid to be pumped or circulated. Characteristics such as viscosity, density,
surface tension and compressibility, along with characteristics of the system
such as require rate of fluid, head to which the fluid is to be pumped,
temperature encountered in the system, and pressure tackled by the fluid in the
system, are taken into account.
Types of Pumps
The pumps used on
board are broadly classified into two types:
Positive Displacement Pump
Positive displacement
pumps are self priming pumps and are normally used as priming devices.
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They consist of one or more chamber,
depending upon the construction, and the chambers are alternatively filled and
emptied.
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The positive displacement pumps are
normally used where the discharge rate is small to medium.
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They are popularly used where the
viscosity of the fluid is high.
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They are generally used to produce
high pressure in the pumping system.
Dynamic Pressure or
Roto-Dynamic Pump.
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In dynamic pressure pump, during
pumping action, tangential force is imparted which accelerates the fluid
normally by rotation of impeller.
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Some systems which contain dynamic
pump may require positive displacement pump for priming.
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They are normally used for moderate
to high discharge rate.
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The pressure differential range for
this type of pumps is in a range of low to moderate.
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They are popularly used in a system
where low viscosity fluids are used.
These broad classification of pumps are further differentiates
by their constructional properties and popularity of usage onboard ship;
Positive Displacement pump:
Positive Displacement pump:
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Reciprocating Pump
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Screw pump
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Gear pump
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Piston pump
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Ram type pump
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Vane pump
Dynamic pressure pumps:
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Centrifugal pumps
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Axial flow pumps
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Submersible pump
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Centrifugal-axial (mixed) pump.
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